This invention pertains to an integrated transmission-engine control wherein the transmission controls engine speed and is integrated with the control of supply of fuel to the engine for matching engine horsepower and transmission-governed engine speed to optimize fuel consumption and with the integrated controls using fluid pressure signals.
Many different types of controls for engines and transmissions driven thereby are known in the prior art wherein an effort is made to have the engine operate with minimum fuel consumption. The assignee of this application has U.S. Pat. No. 3,855,793 which describes one type of control system and refers to prior devices. The system disclosed in the patent provides for an operator to set engine horsepower by the supply of fuel to the engine and with the transmission ratio being adjusted to have the engine speed operate at the given horsepower and at a particular speed as governed by the transmission for minimum fuel consumption.
The Croswhite U.S. Pat. No. 3,237,398 discloses a control system which reduces engine horsepower by means of lowering engine speed (on the lug curve) with a transmission ratio change in order to limit working pressure. The system is used primarily as a pressure control and not an engine speed control and there is no provision for decreasing fuel to the engine.
The prior art includes various types of acceleration controls to limit acceleration at start-up. However, none are known which control both fuel supply and transmission ratio.